<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button class="submit">点击</button>
    <p>ABC</p>
</body>
<script>
    //write会重新绘制html画面，覆盖原来的画面。
    let btn = document.querySelector('.submit');
    btn.onclick = function(){
        document.write("<div>abc</div>");
    }
</script>
</html>